Caution stupid questions follow ... My son (age 13) and I (age old) are considering do some USPSA (SS 1911s) events next year so I have been doing some studying: Why do so many holsters, etc list as being IDPA approved but few it any mention USPSA? Do the majority of you reload or use factory ammo? If factory, are they full power? My son is timid over full power 45s. We are planning on shooting 1911 in the SS division. What simple mods are allowed ie-sight swaps, magwell, checkering? We scoped out an event last year but that was a lot to absorb. Any other info and advice would be appreciated. Trying to be prepared and not look like the newbie that I am.